On Fri, 15 Apr 2022 at 20:40, Steven D'Aprano <st...@pearwood.info> wrote: > > On Thu, Apr 14, 2022 at 10:46:46AM +1200, Greg Ewing wrote: > > On 13/04/22 8:29 am, Steven D'Aprano wrote: > > >>When multiple parent provide candidate to a method resolution, raise an > > >>error. > > > > > >Then you aren't doing full MI any more, > > > > That sounds like a "true Scotsman" argument. Who defines what > > "full MI" means? > > If you look at languages that implement MI, and pick the implementations > which allow it with the fewest restrictions, then that is "full MI". >
I'm with Greg on this one, for the simple reason that a future language could have fewer restrictions than Python does, and therefore would become the only thing that offers "full MI", displacing other languages. It's a meaningless concept, unless there is some form of absolute completeness that can be attained (and if you go for that, NO language offers "full MI"). My view: If a class inherits two parents, in any meaning of the word "inherits" that follows the normal expectation that a subclass IS an instance of its parent class(es), then it's MI. So if you have "class Foo(Spam, Ham):" and it is reasonable to treat a Foo instance as if it were a Spam instance *and* reasonable to treat a Foo instance as if it were a Ham instance, then it's MI. Erroring out when there is a conflict is a restriction, but I would avoid the term "full MI" because it's more emotive than useful. ChrisA _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/HRBMHDQSAAAWWXNBGMVXKIB34QHKYFBO/ Code of Conduct: http://python.org/psf/codeofconduct/
